Abstract: The oxidation resistance of Si₃N₄-ZrO₂ composite under high stress was investigated. The experimental results were as follows:(a)The oxidation resistance of Si₃N₄-ZrO₂ composite depended mainly on the amount of ZrN which was formed during sintering. When some ZrN was formed on the surface of sintered samples,the sample was oxidated quickly under high stress at 1100℃. On the other hand,when some Si₂N₂O was formed or no ZrN on the surface of the sample,the sample was very difficult to oxidate. (b)The thermal shock resistance and compressive stress at high temperature of Si₃N₄-ZrO₂ composite were better.